Thermochemistry of drugs: experimental and theoretical study of analgesics

Abstract

Acetanilides are broadly used in the pharmaceutical industry. Thermochemical data on vapor pressures, solid-gas, liquid-gas, and solid-liquid phase transitions, as well as on enthalpies of formation of substituted acetanilides have been collected and evaluated with help of additional experimental measurements. Absolute vapor pressures of meta- and para-substituted acetanilides were studied by using transpiration method. Significant disagreement of available literature data on isomeric hydroxyacetanilides was detected and resolved. A quick estimation scheme of vaporization enthalpies of substituted acetanilides at 298.15 K was developed based on “structure-property” relationships. Quantum-chemical methods were applied for calculation of theoretical gas-phase enthalpies of formation of substituted acetanilides. Theoretical values together with results from “structure-property” analysis allowed for validation of the experimental crystalline state enthalpies of formation and prediction of these values based on quantum-chemical calculations.

Notes

Acknowledgments

We gratefully acknowledge the contribution of Dr. Vladimir N. Emel’yanenko for quantum-chemical calculations.

Funding information

This work has been partly supported by the Russian Government Program of Competitive Growth of Kazan Federal University. R.N gratefully acknowledges the financial support by the research grant of Kazan Federal University and the financial support by the Russian Ministry of Education and Science No. 4.5289.2017/9.10. B.S. and gratefully acknowledges the financial support by the Russian Ministry of Education and Science No.4.5618.2017/6.7. This work has been partly supported by the German Science Foundation (DFG) in the frame of the priority program SPP 1807 “Control of London Dispersion Interactions in Molecular Chemistry”, as well as of the priority program SPP 1708 “Material Synthesis Near Room Temperature”.